crepl

commit c03f80677c5cbd132894a512172ce54548ed8cc9
parent 0f0ef3b11642e230165fafb8686ea0addf869485
Author: Demonstrandum <moi@knutsen.co>
Date:   Fri, 26 Jun 2020 12:31:26 +0100

Prevent some segfaults.

Diffstat:
M
.gitignore
 | 
1
+
M
Makefile
 | 
1
+
M
src/execute.c
 | 
4
++++
M
src/parse.c
 | 
13
++++++++++---

4 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -9,3 +9,4 @@ crepl
 *.log
 desktop.ini
 .DS_Store
+IDEAS.md
diff --git a/Makefile b/Makefile
@@ -13,6 +13,7 @@ endif
 all: clean $(TARGET)
 	@printf "\033[1mBuilt \`$(TARGET)' successfully.\033[0m\n"
 
+debug: CFLAGS := $(WARN) -Og
 debug: $(OBJS)
 	$(CC) -Og -o $(TARGET) $(LINKS) $(OBJS)
 
diff --git a/src/execute.c b/src/execute.c
@@ -119,7 +119,11 @@ finished_search:
 
 		// How to evaluate specific operators.
 		DataValue *lhs = execute(ctx, stmt->node.binary.left);
+		if (lhs == NULL)
+			return NULL;
 		DataValue *rhs = execute(ctx, stmt->node.binary.right);
+		if (rhs == NULL)
+			return NULL;
 
 		// Numerical binary operations.
 		if (strcmp(op, "+") == 0) {
diff --git a/src/parse.c b/src/parse.c
@@ -385,7 +385,10 @@ ParseNode *parse_infix(const ParseNode *left,
 			unary->callee = node;
 			unary->operand = left;
 			unary->is_postfix = true;
-		} else { // Function call.
+		} else { // Function call, probably.
+			if (token->type == TT_OPERATOR)
+				return NULL; // Not a real operator, not a function.
+
 			unary->callee = left;
 			// The minus one (- 1) makes function application right
 			// associative, this is unconventional, and makes applications
@@ -394,6 +397,8 @@ ParseNode *parse_infix(const ParseNode *left,
 			// by juxtaposition.
 			// e.g.  3 sin 2  =>  (3 (sin 2)) vs ((3 sin) 2)  [<- error]
 			unary->operand = parse_expr(rest, FUNCTION_PRECEDENCE - 1);
+			if (unary->operand == NULL)
+				return NULL;
 			unary->is_postfix = false;
 		}
 
@@ -498,8 +503,10 @@ ParseNode *parse_expr(char **slice, u16 precedence)
 		current_precedence = token_precedence(token_ahead);
 	}
 
-	free_token((Token *)token_ahead);
-	free_token((Token *)token);
+	if (token_ahead != NULL)
+		free_token((Token *)token_ahead);
+	if (token != NULL)
+		free_token((Token *)token);
 	return left;
 }